new file:   clean-all-deps.sh
checkpointing commits. strange segfault happening
	modified:   .gitignore
Comment about load error than occurs < 1/10 times.
Some kind of race condition ?
	modified:   src/primesieve_c.jl
add some nextprime tests
	modified:   test/primecount_test.jl
checkpointing still.
	modified:   test/primesieve_test.jl
reinstate all tests. segfault mysteriously disappeared
	modified:   test/primesieve_test.jl
try to fix compatibility issue. no luck.
update for improve signal handling in msieve